The only mandatory thing is a bike all else is optional. Good gear should come first, then a cage. after that a steering damper is key to long endos. gearing and handbrake are good, once youve learned the basics. an oil pickup is needed for alot of bikes. all the mods in the world wont help if youre afraid to lay down your bike, I recomend a beater with a cage and some good gear, thats the fastest way to progress, not being afraid to fail learning. Good luck!